In a distribution warehouse in which cargo, such as merchandise, is stored and from which the stored cargo is ultimately shipped, an unloading apparatus may be used to unload cargo items onto a conveyer belt or the like. An unloading apparatus that includes a robot arm with a cargo grasping unit, such as a suction unit, provided on a tip end of the robot arm, is known.
Items of cargo are conveyed to the unloading apparatus in a palletized state (stacked on a pallet). The unloading apparatus may image the cargo grouping on the pallet with a camera positioned above the cargo group, measure the position of each item of cargo based on information acquired from the imaging of the cargo grouping, and then pick the items of cargo one by one from the grouping, and then place the items of cargo individual onto the cargo conveyer or a storage shelf for later distribution.